Conventional sandwich panels have a core material manufactured by using a material such as balsa wood or foamed plastic for lightweight or by using a honeycomb structure made of a metal material for improvement of sound insulation, flame retardancy, etc. However, general sandwich panels including such a core material have problems in that interlayer bonding force is weak or strength is weak, and thus, moldability is poor when it is processed into various shapes. In addition, there have problems in that when a metal material is included as a core layer for a process requiring electrical conduction between panels, such as welding, the weight of the sandwich panel becomes too heavy and the manufacturing cost increases.
For example, Korean Patent No. 10-0786335 discloses a sandwich panel for interior and exterior materials, including a balsa wood panel. The balsa wood panel includes a unit panel and a heterogeneous material panel formed of any one of a cork material and a resin material, and has purposes for lightweight and improvement of sound insulation. In addition, Korean Laid-open Patent Publication No. 10-2009-0064837 discloses a sandwich panel for a vehicle having a paper honeycomb core and support sheets bonded to both sides of the honeycomb core, including adhesive layers interposed therebetween. The sandwich panel having the honeycomb core is intended to secure rigidity relative to weight and the low manufacturing cost and to obtain an effect of in-mold molding. As described above, the sandwich panel having the balsa wood or the honeycomb core has limitations in view of prevention of interlayer delamination and prevention of wrinkle occurrence in implementing various shapes through molding including a large degree of modification. Therefore, there is a need for research on a sandwich panel capable of overcoming the structural limitations for excellent moldability while simultaneously securing a high level of support performance and mechanical properties.